Tunnel kiln



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EIASZST R. H. MILLER TUNNEL KILN Filed April l5. 1922 5 Sheets-Sheet 2 l. l nwmw Awww@ hm. A

jan. 29, 1924.

' 1,482,087 R. H. MILLER TUNNEL KILN Filed April 15,1922 5 sheets-sheet 5 Jan. 29,1924. 1,482,087

R. H. MILLER f TUNNEL KILN Filed April l5, 1922 5 Sheets-Sheet 4 jam 231, T1924. @,z

R. H. MILLER TUNNEL KILN Filed April 15 1922 5 sheets-sheet 5 Patented dan.. 29,'-. 1924'.

. norm H. MILLER, or sr. Louis, MISSOURI.

TUNNEL mu.

To all 'whom concern:

Be it known that I, ROBERT H. MILLER,

a citizen of the United States, residing at- St. Louis, State of Missouri, have invented 5 certain new and useful Improvements in Tunnel Kilns, of which the following is a specification, reference .being had therein to the accompanying drawings.

My invention relates to improvements in tunnel kilns and more particularly to railroad tunnel kilns for burning and annealing products, such as bricks, in which the operation is continuous.

There are now three distinct types of tunv nel kilns, namely, the muflle type, the open type and the composite mule and open type.

Inthelmufile type the combustion takes place in an enclosed chamber; the heat is confined in the muflle; the combustion gases lead to exhaust through a series of muflles,

and the burning and preparing done by radiation alone.

In the open type the combustion takes place in the ware and the gases are led to the exhaust through the ware.

In the composite mufile and open type the combustion takes place in the ware and the gases immediately`-led Yinto a recuperator and thence-to exhaust.

In all such types, the kilns operate on what is known in practice,l as the up-draft principle, in which the combustion ases are .con-

ducted in a substantially horlzontal plane,

or course, to openings, usually in the side walls, near the entrance end of the kiln.

Naturally, in all such kilns the combustion gases have a tendency to rise to the top, or arch, and to move in paths of least re sistance, along the top of the kilns with the 4o result that the preparing of the ware is advanced along the top and the up per sides7 and the centers and bottoms improperly prepared, or retarded Numerous lexpediente have been resorted to in efforts to control the flow of combustion gases to force thevheat to the center ,and lower sides of the ware, suchas backpressure devices, which, so'far have re' sulted in producing unsatisfactory conditions in the preparing zone and operated -to effect non-uniform performance of the kilns generally. i

In such of the present kilns, where attemptsto recover the heat from thematerial in l Application led April 15, 1922. Serial No. 552,843.

the cooling zone are made the currents of air, usually by means of a pressure blower, are forced to travel in apath distinct from the path of theimateriaLtoward `the discharge end ofthe kiln under the conveyor and thence back through the kiln in the path of the material. Obviously, and for the same reason as recited in connection with the preparing zone, the tendency is for the cool currents to follow along the bottom' of the ware, thereby causing the upperware to lose its heat in a slower manner than the lower ware.

At present, all kilns, having conveyors for the movement of the ware'through the kiln, employ conveyors, such as cars or trucks, having solid, imperforate bottoms, or beds, hence the circulation of currents, whether in the preparing, treating, or cooling zone must of necessity be around the sides and top of the material and in a path paralleling the trend of the kiln.

In -substantiation of the contention that the present kilns are. operating at an efiiciency widely separated from maximum it is pointed out that the product of all kilns is now subjected to grading, and, that such grading includes seldom less than three distinct conditions of material. These conditions are created by inability to properly control and distribute vthe currents in the preparatory stages of burning.

The primary object of my lnVention isto provide an apparatus comprising a ware conveying means, and a confining means surrounding the. path of travel of the conveying means, adapted to effect a substantially uniform condition of treating medium throughlout said confining means, whereby all of a quantity of materialconveyed throu h said confining means will be uniformly sujected 95 to said treating medium.

A further object of my invention is to provide an apparatus comprising an open work conveyor, a confining means surrounding the Y ,path of travel of the conveyor and means for controlling the movement of a treating medium in paths out of lparallel with theV trend of the confining means whereby material carried on the open work conveyor will be subjected to currents of such treating 105 medium whose trends are angular to the path of the conveyor, .to the end that such material is uniformly treated.

85 elevation, taken on the line indicated 5 5 i by the conveyor.

With the above mentioned, and other, objects, as will be revealed, in view, my improvements consist in the novel construction, arrangement and combination of parts as will be fully, clearly and concisely described. definitely pointed out in my claims and illustrated by the accompanying drawings, (5 sheets) in which- Figure 1 is a longitudinal sectional ele` vation of a. kiln constructed in accordance with my invention, and in which arrows indicate the course of treating medium.

Fig. 2 is a sectional plan viewof the kiln illustrated in Fig. 1

Fig. 3 is an enlarged transverse sectional elevation,taken on the line indicated 3 3 of Fig. 1 showing the drying chamber or zone.

Fig. 4 is an enlarged transversesectiona'l" elevation, taken on the line indicated 4 4 of Fig. 1, showing the preparing zone.

Fig. 5 is an enlarged transverse sectional of Fig. 1 showing the burning zone.

Fig. 6 is an enlarged transverse sectional elevation, taken on the line indicated 6 6 of Fig, 1, showing `the cooling zone.

Fig. 7 is a plan view of one of the cars, showing its open-work' bottom. l, Fig. 8 is a longitudinal sectionalgelevation of the car taken on the line indicated 8 8 of Fig. 7, and Fig. 9 is a transverse sectional elevation of the car taken on the line indicated 9 9 of Fig. 7.

In the form of apparatus illustrated the kiln proper comprisesv opposed parallel side walls 10 which` are spanned by an arch, or top 11, which together form a tunnel through which material to be treated is moved. At each end of the kiln proper, entrance and discharge ends, these is provided a closure, suchas the doors 12 and 13, which may be of theprdinary sliding variety, whose specific construction forms no part of my invention.

On the ground, or floor of the tunnel, paralleling the side walls are the rails 14 for the support of ware carrying cars 15, whose beds, hav-ing open work, or grills liform the bottom of the kiln proper or treating zones, and upon which the treated material is moved through the kiln.

B y preference, and as shown, the tunnel lengthy-includes a drying chamber 17, in

communication with the kiln proper through j the -recitedentrance door 12 and which is provided with a receiving door 18.

Paralleling and preferably coextensive in length with the drying chamber 17 is a conduit 19, having an inlet 20, for the drying medium, preferably a plurality of mouths, 21, opening directly into the chamber through the open-work, or grill, of the vware conveyor, or cars 15.

By preference, the inlet 20 resides adjacent the discharge end of the drying chamber, the recited mouths 21 areA relatively spatially related and disposed-with relation to the length of the drying chamber as to establish and maintain a graded temperature lengthwise of the drying chamber, and the drying chamberis provided with an outlet, preferably .in the form of a stack such as 2 2, leading from the chamber, preferably through the top or arch 11, adjacent the receiving end 4of the drying chamber.

The portion of the tunnel length next the receiving end, at the door 12, hereinafter referred to as the preparing Zone', is provided with a conduit 23, (similar to the described conduit 19) which extends parallel with the preparing zone and is in communication with a portion of the length thereof through mouths 24, similar to the recited mouths 21 and which conduit is provided with an outlet 25. i

For economy, I preferthat the outlet 25 of the preparing zone be in communication with the inlet 20 of the drying chamber, as indicated in Figs. land 2, and for the control of the iow of medium in the preparing zone and be-tween the preparing zone and drying chamber l provide a blower, or other inducer as at 26, and a damper controlled 'stack as at 27.

That portion of the tunnel length next the preparing zone and hereinafter referred to as the treating and burning Zone is provided with an outlet in the form of spatially related mouths 28. which communicate with the recited conduit 23, which conduit is extended beyond the preparing zoneto include the mouths 28, or outlet of the treat ing zone, and adjacent the discharge end of the itreating zone, preferably through the side walls of the kiln as shown are the burner openings 29, for the dischargeof fuel into the treating zone. Through the openings 29 the combustible is released, and, coming in contact with the heated air, from the cooling ware, forms the complete comthe cooling zone is providediwith a conduit.

30 similar to the recited conduits 19 and 23, having an outlet, in the form of spatially lll) related imouths and an inlet 32, which by preference is equipped with an inducer such as a blast fan, or blower, 33.

In the immediate foregoing description the kiln is related to the direction of travel riers, cars 15, each of whose lengthsmay be,

for example, six feet, vthe preparing -and treating zones each of a length to include fifteen of the cars, and the cooling zone of a length to yinclude eleven of the cars.

Each of the cars 15 com rises a bed or bottom 34, constructed of re actory or heat resistin material as best shown in F ies. 7 g 7 D 9 8 and 9, having an opening 35 approximate- 1y centrallydisposed in which is supported ,the .recited openwork or grill 16 and surrounding which opening is the dependent lip or iange 36. The bed is supported on a frame 37 comprising a wheeled for travel on the recited rails 14.

For the protection of the running gears of the cars, the metallic frames 371 and wheels 38, against exposure to the excessive heat of thetreating zone (seeFig. 5), I have provided a dead wall section 39, which forms a continuation of the conduits 23 and 30, whose upper surface approximates the plane of the depending flanges-36 of the cars, and augmenting this expedient I have provided parallel troughs 40, containing substance such as sand arranged for traverse byv depending blades 41 carried by the cars, so that-circulation is prevented by either the heat'from the treating chamber reaching the running gears through the openings in the cars, or air being drawn from underneath the cars into the treating chamber.

In addition to such troughs and blades and to prevent travel of air or gases length- Wise/of the kiln beneath the car beds or kiln bottom I have provided the lateral sealing troughs such as 42 (see Fig. 8) which are preferably in communication-with the lon 'tudinal trou hs and coact with cross bla es 43, pivotal y carried by each car to fall by gravity into the troughs 42.

To seal the joints between the car ends I form the ends of the beds as rabbets which form grooves, extending laterally or crosswise of the tunnel bottom, in which I place sand, or its equivalent, and thus prevent communication from the tunnel proper to the air space` surrounding the tracks and running gear, as best shown in Fig. 8.

Augmenting the'control of treating medium as by the relative disposal and arrangement of the various inlets and outlets, such as the mouths 24 and 28 I provide dempers such as 44 at each mouth whereby insane@ the drying zone may be ofsupport 38' each mouth may be active or inactive as desired. And further control, especially' in,"

.relation to 'obtaininguniform treatment `at ,the burning zone, is provided by arranging the 'burner openings 29 at-varying altitudes,

whereby the material in -its movement relative vto the burning zone willbe subjected to heat issuing from sources oocupying posiing step is distinct 1 from the remaining steps and in all kilns distinct-apparatus including the conveyor, or cars, is emloyed, which means that the material after been dried must be reset or transferred from the conveyor of the drier to the/conveyor of the kiln proper. g l

In the provision of a conveyor, or car, havin an open work bottom, and in the construction of the drier, with relation to its inlet for heated currents, identically like the construction of the kiln proper obviously the same cars may be employed in both the drier and the kiln, hence thehandling of material is minimized,

By reason of the placement of the drier in direct ware communication with the kiln proper, or preparing chamber, or zone, the ware is constantlyl maintained in a controlled temperature or condition,'and such controlled temperature or, condition may be. made substantially similar between the discharge end of the drier and. the receiving end of the preparing zone so that the ware need not be subjected to too in treating condltions By reason of theutilization of the treating Ymedium from the preparing zone to eii'ect the drying, an ideal condition in the aving rapid changes y drier is obtained for the reason that such medium, isladen with considerable moisture which in the presence of heat causes a humidity which effects more rapid and uniform drying of the ware, and practically Aeliminates checking or face cracks dueto too rapid surface drying.

The operation of a kiln constructed in j as desired and their courses directed in the drier as desired and by reason of the inlets being beneath the material the treating currents are caused to be moved vertically as well as longitudinally through the material, instead of only along the top and upper sides as in the present kilns.

Assuming all of the various zones to conprogressively with tain cars laden or set, as recited, the drier" troduced to be moved through and dis-` charged from the various Zones;

Obviously upon the introductionof a car into the drier,A or the entrance end of the kiln a car will be moved out of the discharge end of the cooler. `The movement of the tra-in of cars is thus unitary in which the openings in the car bottoms are step by step related to and brought toA register the mouths 21 of the drying zone; mouths 24 of the preparing zone; mouths 28 of the burning Zone an mouths 31 of the cooling zone.

Obviously further, the materials in the preparing Zone, by reason of the arrangementv of,the outlets 24 will be caused to travel in a heated current of substantially uniform temperature throughout the height ,of the kiln and by reason of the open bottom cars such currents will be caused to bemoved through the material both vertically and horizontally hence the .centers reached andproperly prepared, which action is not accomplished, or is possible, in thev present kilns by reason of the employment of solid bottom conveyors, or cars.l

In the treatin or burning, zone vby reason of the descri ed arrangement of burner 'openings and the arrangement of the outlets or mouths 28 the currents may be controlled and directed to tra-vel in selective planes for uniformity of temperature throughout-the height of the kiln for the whole len h of the treating zone and by reason ofthe open'stacked material and the open bottomed cars the heatedfair forced through the centers of the material.

In the cooling zone by reason of the described construction the cooling medlum, at-

mospheric air acts to uniformly cool the material.

I claim: i 1. In an apparatus of the class described,

a confining means, a conveyor arranged for movement through the confining means, and means for directing a treat-ing medium to travel lengthwise through said confining means and vertically through said conveyor. 2. In an apparatus of the class described, a confining means, an open bottom conveyor arranged for movement through the confining means, and means for directing a treating medium to travel lengthwise through said confining means and vertically through said open bottomed conveyor.

' 3. In an apparatus of the class described,

a confining means, a conveyor arranged for means? movement through the confining means, and means comprising spatially related mouths for directing a treating medium to travel longitudinally of the confining means and vertically throughaid conveyor.

4. In an apparatus of the class described, a confining means, a conve or arranged for movement through the con ning means, and means, comprising controllable inlets and outlets spatiallyelated along the trend 0f the confining means for directing a treating medium to traverse the confining means in selective planes.

5. In an apparatus of the class described, a confining means, an open bottom conveyor arranged for movement through the confining means, and means comprising controllable inlets and outlets spatially along the trend of the confining means for directing a treating medium to traverse the confining means in selective planes and to direct such medium to be moved vertically through the open bottom conveyor.

6. n an apparatus of the class described, a conning means, comprising a movable bottom, forming a ware conveyor, means for introducing a treating medium in the confinin means for travel in the trend of the con ning means, and an outlet comprising a plurality of spatially related mouths for controlling the plane of movement of the treating medium through said confining means.

7. In an apparatus ot' the class described, a .confining means comprisinga. movable bottom, forming a ware conveyor, having openings therethrough at intervals, means for introducing a treating medium into the confiningv means for travel inthe trend of the confining means, and an outlet comprising a plurality of mouths spatially related and arranged for register 'with the recited openings in the ware conveyor whereby the fiow of currents of the treating medium may be directedA in its travel to flow lengthwise through the ware as well as vertically therethrough.

8. In an apparatus of the class described, a confining means, comprising a movable bottom forming a ware conveyor, having openin s at intervals, means for introducing a treating medium into the confining means for travel in the general trend thereof, and an outlet comprising a plurality of controllable mouths arranged for registration with the recited openings in said movable bottom .whereby currents of said treating medium may be caused to moved in selective planes in the trend of the confining means and caused to moved vertically through the said openings and mouths.

9. In an apparatus of the class described, a confining means, comprising a bottom forming a ware conveyonhaving openings therethrough at intervals, means for introrelatedy t dfi ducing treating medium into the conining means'for travel in the general trend thereof, means for dividing the confining means to form distinct compartments, means comprising spatially related mouths for communication with the recited openings in said bottom for controlling the' movementof the treating medium through Said distinct compartments.

10. In an apparatus of the .class described,

a tunnel, movable closures at the entrance' and discharge ends of the tunnel, a movable closure intermediate the entrance and discharge ends to divide theftunnel into distinct compartments, means common to said compartments. for the conveyance of ware therethrough, means for introducing a treating medium into one of said compartments and means for controlling the movement of said treating medium causing it to travel throu h4 all of said compartments in selective p anes. v

11. In an apparatus-of the class described, a tunnel, ware conveyingmeans arranged for movement through the tunnel, means intercepting the path of the ware to divide the tunnel length into distinct drying and treating zones, means for introducing oombustion gases into the treating zone, means for conducting currents from the treatingy zone to the drying zone and meansfor introducing` into the tunnel length atmospheric air for the creation of acooling zone in ad .Vance of' and in direct communication with the treating z one, v whereby ware carried upon said conveying means will be subjected.

to drying, preparing, burningand cooling treatments Awithout handling and without exposure to other than controlled temperatures and conditions.

12. In an apparatus of the class described, a tunnel, a ware conveying means' having openings at intervals forming the bottom proper ofthe tunnel, means for introducing" combustion gases into the tunnel above' said vvtom and means for preventing exposure of bottom, an outlet for said combustion gases comprising a plurality of' spatially related mouths beneath said bottom .for communication with the recited openings in said bottom, whereby a preparing-'and burning zonel is established, means Aforl establishing communicationbetween said outlet and a distinct inlet-comprising a similarly arranged pluralit of mouths whereby a drying zone is estab ished in advance of the preparingan'd, burning zone and an inlet comprislng' a third distinct plurality of mouths following `the burning zone whereby a cooling zone isestahlished whereby `ware in its vtravel through thetunnel will be subjected'to 'currents di treating mediums both longitudinally and vertically therethrough.

13. In an apparatus of the clam described,l having a drying zone, a preparing and burn*- ing zone and a cooling z one, a

means common to -all of said zones, a bottom common to all of said zones, in the form of a, ware conveying means, andwhich bottom is provided with openings lat intervals in its length, an inlet to said cooling zone comprising a plurality of spatially related mouths beneath said bottom and in communication with the zone through the openings in said bottom whereby the burned ware carried upon said conveyingmeans will be subjected'te currentsl of cool air through the comprising a plurality of spatially related" mouths beneath said bottom and in communication with the drying zone through the openings in said bottom, means for establishing and controlling communication between the outlet of the preparing zone and the inlet of the drying zone, an outlet for the Vdrying zone and movable closures at the receiving ends 'of the drying and preparmg zones and at the 'discharge end of the coolin zone.

14. n a kiln, -a tunnel, a track-way on the iioor of said kiln, a ware conveyor in the V form of cars, having metallic frames and wheeled supports, and beds of refractory material, said 'beds forming the bottom proper of the kiln, means for directing currents of treatin medium to move in 'a controlled course t rough the tunnel and vertically through openings in said tunnel botsaid track-Way, said metallic frames and wheeled supports of the conveyor cars to said treating medium and to prevent air tunnel proper.

15. In a tunnel kiln, a ware conveyor, comprising cars having wheeled su ports, and whose beds form, the bottom of't e tunnel, there being openings in said beds, in-

prising mouths located beneath and for com munication with the openings in saidcar beds, sand containing sealing troughs surrounding said mouths and blades carried by the cars for coactlon with said sand center of the masses of ware as well as along l l lets and outlets for treating medium com-v troughs for sealing around said openings and mouths. l

` 16. In a tunnel vkiln, a ware conveyor forming thebttom of t e tunnel 'and probeing drawn from under said bottom to the n.5

vided at longitudinal. intervals with openings extending vertically therethrough, inlets and outlets for treating medium com prisin-g mouths located beneathl and for communication with the openings in the Ware conveyor, and means for sealing about said openings and mouths comprising e1ements resident at said mouths and elements carried by the conveyor for coaotion therewith.

In testimony whereof I hereunto affix my signature.

ROBERT H. MILLER. 

